An official for Facebook told TechCrunch that the company is “continuing to cooperate with the relevant U.S. authorities,” as investigations into the Russian hack of last year’s presidential election continue to expand. In the latest development, authorities are now investigating how agents used online advertising on social networks and search platforms, and tech companies are being forced to hand over new, sensitive information to investigators as a result.

Facebook has apparently turned over more detailed information to the special prosecutor, Robert Mueller, than the company shared with Congress last week, the Journal reports.

Mueller’s investigation has received copies of the Russian-bought ads and details about the specific account information and targeting criteria the buyers used to distribute their ads, according to the Journal, citing people familiar with the matter.

It’s likely that Facebook was compelled to turn over the information because the investigating team received a search warrant.

If indeed, Mueller is using warrants, then it’s likely that Facebook won’t be the only tech company that may be forced to reveal information about potential clandestine advertising buys, which Russian agents are alleged to have made in order to influence the U.S. election.

The Journal reports that Mueller’s team could have gotten information that Facebook withheld from Congress because of concerns around privacy laws or fears of disrupting the Mueller probe. My guess is that Facebook is likely also thinking that the Mueller investigation is a tighter ship and less likely to leak details of the ads whereas Congressional staffers could leak like sieves.

It’s clear that Facebook has no interest in revealing details of the ad buys, or telling individuals whether they were targets of what amounts to a Russian plot to influence the U.S. election.

It’s something members of the tech community have taken Facebook to task for already.

Secret political ads are by definition an attack on democracy. Their disclosure is not optional. Shocking FB continues to insist otherwise.

It was part of a broader report that indicated 500 “inauthentic” accounts linked to Russia had purchased 5,000 ads from the company. The developments today relate to that same trove but are a sign of yet more data now being handed over to authorities.

Last Wednesday, as the company released its assessment, Facebook representatives also spoke to Congress as part of ongoing House and Senate investigations into Russian interference in the election. Facebook even told The Washington Post, “there is evidence that some of the accounts are linked to a troll farm in St. Petersburg, referred to as the Internet Research Agency, though we have no way to independently confirm.”

As we reported, the Internet Research Agency is widely known for its pro-Kremlin online propaganda campaigns, which U.S. intelligence agencies believe is backed by someone with close ties to the Russian intelligence community who is a close friend of Vladimir Putin’s.

Facebook’s disclosure was the first time it admitted that Russians had reached out to voters during the elections. The company had previously denied that there were any ad buys made by Russian agents or anyone connected with the Russian government.

All of these discoveries and announcements come amid serious questions about the role of Russia in the last election … and whether the President Donald Trump’s campaign (or people associated with that campaign) colluded with the Russian government.

Committees in both houses are writing up reports on the role Russia played in the election.

It’s also worth noting that Facebook isn’t the only social media company to come under fire for either unwittingly or knowingly playing a role in disseminating propaganda on behalf of a foreign government.

Twitter is also expected to come before congressional inquisitors in the coming weeks, according to a report from Reuters last week, quoting Democratic Senator Mark Warner.

“It was my belief that the Russians were using those sites to interfere in our elections, and the first reaction from Facebook was, ‘No. You’re crazy.’” Warner said at the Intelligence and National Security Alliance conference in Washington.

“I think what we saw yesterday in terms of their brief was the tip of the iceberg,” Warner said.

He also told reporters he expected Twitter to soon brief the Senate Intelligence Committee, one of the panels investigating Russian meddling in the 2016 election and whether members of President Donald Trump’s campaign colluded with Moscow.

Facebook has been reluctant to share any details with the public and have extended that reticence to the Congressional investigators that are looking into Russian interference. The Journal reported that Facebook believes the data on ads could be protected under the Electronic Communications Privacy Act.

Bi-partisan leadership from the Senate Intelligence Committee is pushing for company representatives to come to Capitol Hill and publicly walk Senators through how potential Russian agents came to advertise on the company’s social network.

The Senate could compel Facebook executives to show up by issuing a subpoena… But subpoena power to testify is not the same as a warrant. Search warrants have more legal force behind them and mean that the company has to disclose more information than it would in live testimony.